1. Field of the Invention
The subject invention is related to a method and apparatus for mounting a heavy load on a transport vehicle in such a manner that the load may be moved between a stowed position and an operating position along a vertical path and is particularly directed to a method and apparatus for mounting a frac blender.
2. Discussion of the Prior Art
Fracturing was first employed to improve production from marginal wells in the late 1940's. Following an explosion of the practice in the mid-1950's and a considerable surge in the mid-1980's, massive hydraulic fracturing grew to become a dominant production/stimulation technique, primarily for low permeability reservoirs in North America. By the mid-1990's, forty percent of new oil wells and seventy percent of gas wells in the United States were fracture treated. With improved fracturing capabilities, and the advent of high permeability fracturing, the practice has expanded further to become the completion of choice for all types of wells in the United States, but particularly natural gas wells. The tremendous advantage in fracturing most wells is now largely accepted. It is estimated that hydraulic fracturing may add several hundred thousand barrels per day from existing wells throughout the world.
Hydraulic fracturing entails injecting fluids in an underground formation at a pressure that is high enough to induce parting of the formation. Granulated materials, called proppants, which range from sand to synthetic materials are pumped into the created fracture to create a slurry. These proppants hold open the created fracture after the injection pressure is relieved. The fracture, filled with proppant, creates a narrow but conductive flow path toward the well bore.
In order to facilitate fracturing of existing wells, workover equipment includes a transportable fracture blender, or frac blender, for creating the slurry at the well site. Typically these transportable frac blenders are mounted on trailers or truck beds or a similar transport vehicle. A typical frac blender weighs several tons. It has to be moved into position and placed at or near ground level during operation.
Prior art transportable frac blenders are mounted on the rear of the transport vehicle and moved from a raised or stowed position permitting movement of the vehicle to a lowered operating position at the job site. Typically, the frac blender is mounted on a hinged lift mechanism and moves through an arc about a “hinge” to rotate the blender from the upper stowed position to the lower operating position. This is an awkward mounting system at best and places tremendous stress on the hinge system as well as the drive system for moving the blender between positions.
In addition, such massive units are difficult to keep in balance during movement between positions even under the best of circumstances, creating a hazardous rollover potential. In the field, where uneven terrain is often present as well as numerous environmental conditions, it is difficult to maintain balance and the resulting binding stresses can generate wear and tear and frequent breakdowns.
While such systems have gained widespread acceptance, it remains desirable to provide a more dependable apparatus and method for mounting and transporting frac blenders.